1. Technical Field
The present disclosure relates to semiconductor devices, and, more particularly, to impedance tuning circuits and integrated circuits including the impedance tuning circuits.
2. Discussion of the Related Art
As the operating speed of a system having integrated circuits increases, swing widths of signals interfaced between the integrated circuits decrease. A reason for the decrease of the swing widths is to minimize the time taken to transmit the signals. However, as the swing widths decrease, the signals transferred between the integrated circuits can be more easily distorted by an impedance mismatch caused by process, voltage and temperature (PVT) variations. If the signals transferred between the integrated circuits are distorted, setup/hold failure, for example, may be caused by the distorted signals. An impedance tuning circuit for adjusting an output impedance and/or a termination impedance can be employed at transmitting and/or receiving stages of the integrated circuits. However, since conventional impedance tuning circuits require hundreds of cycles to adjust the output impedance and/or the termination impedance by comparing the output impedance and/or the termination impedance with an impedance of an external resistor, the performance of the system can deteriorate while the impedance tuning circuit performs the impedance tuning operation.